1. Field of the Invention
The present invention relates to high voltage circuit interrupting devices, and more particularly, the present invention relates to a compact interrupting device to be used in conjunction with movable conductive elements such as a power fuse or a disconnect switchblade.
2. Description of the Prior Art
Circuit interrupting devices are well known in the art for interrupting current flow in high voltage circuits. Because of the high voltage, a switch is totally unsuited for interrupting current flow in an electrical circuit. Upon opening of ordinary switch contacts, the high voltage causes an arc to be drawn between the separating contacts thereby resulting in the possibility of a short-circuit and consequent damage to the contacts and the surrounding structure. Further, the resultant arc may continue for a long time without interruption.
Accordingly, a variety of circuit interrupting devices have been developed to permit the interruption of current flow in high voltage circuits. For example, the switch contacts have been placed in a vacuum so that there is no gas capable of ionization and arc conduction. Further, prior art interrupter switches have been developed wherein the contacts are surrounded by an ambient atmosphere of an arc extinguishing gas. Further, prior art circuit interrupting devices have been developed utilizing a solid liner and trailer fabricated of a material that evolves an arc extinguishing gas when exposed to an electrical arc. Thus, when the contacts separate, the evolved gas causes the arc to be extinguished. Prior art constructions illustrating conventional prior art current interrupting switches utilizing such solid gas evolving trailer liner arrangements are illustrated in U.S. Pat. No. 3,236,984--Lindell and U.S. Pat. No. 3,792,215--Keto.
Prior to the development of the present invention, several attempts have been made to provide a simple, inexpensive circuit interrupting device that could be utilized in connection with movable conductive elements such as power fuses, cutout fuses, and disconnect switchblades to interrupt current flow during opening. For example, the device illustrated in U.S. Pat. Nos. 2,671,142; 2,671,145; 2,816,978; 2,816,980; 2,816,981; 2,816,983; and 2,816,985 all by Lindell and assigned to the same assignee as the present invention disclose a portable hand operated device known as a "Loadbuster" tool that may be used to open fuses, disconnect switches and other electrical elements under load. U.S. Pat. No. 3,235,696--Mikulecky discloses a load break disconnecting device that is permanently mounted to a disconnect switchblade and a central load break switch that includes a fuse. This device uses a solid nonconducting arc suppressing sleeve that slides over the conducting portions of the switchblade as the switch is opened to suppress the arc and interrupt current.
Despite the variety of circuit interrupting devices presently available, it would nonetheless be a desirable advantage in the art to provide a simple, inexpensive current interrupting device which may be permanently mounted and repeatably used in connection with movable conductive elements in series to interrupt current flow when those movable conductive elements are moved to an open position.